1. Field of the Invention
The present invention relates to a semi-rigid asphalt concrete, which is made by applying the procedure of producing cement concrete, and the semi-rigid asphalt concrete is completely produced after mixing, placing, and curing. And more specifically, the present invention relates to a method for improving the prior art for paving by asphalt concrete without using the steps of high temperature heating and great pressure rolling necessitated by the prior art.
2. Description of the Prior Art
Transportation and trucks' loading keep growing up as industries go on developing, which increases loading of road pavements. An often used conventional skill is to apply hot mix asphalt concrete for paving. By using great pressure rolling and a layer-by-layer scheme, the asphalt concrete is pressed solidly as achieving expectant strength. Any pavement formed from the above scheme is named as flexible pavements, which is tender enough for those who driving cars to feel comfortable. Because the flexible pavement has disadvantages such as deformation, cracking or slipping by great pressure of wheel tracking, the structure of the flexible pavement is easily destroyed.
Another technology applies cement concrete for paving, which is named as rigid pavement. The cement concrete provides higher strength than the conventional asphalt concrete in deformation resistance from wheel tracking. Because the strength and the rigidity of the cement concrete are stronger than the asphalt concrete's, it implies the cement concrete makes drivers to feel less comfortable than the asphalt concrete does. In addition, a higher cost and more difficult technologies are needed for construction. Otherwise, hard to maintain is another disadvantage of the cement concrete. It also indicates that both of the hot mix asphalt concrete and the cement concrete still need some improvements.
The hot mix asphalt concrete is sometime applied as filler source with additional cement, wherein the quantity of the additional cement must be limited in a weight range of 10% to 15%. Unfortunately, additional strength generated by the additional cement does not significantly increase. The cement has been conventionally applied as additions in the emulsified asphalt concrete in a weight range of 0.5% to 2%. Evaluations from the emulsified asphalt concrete indicate that the stability and the flow of the emulsified asphalt concrete significantly increase. Furthermore, the coating capability of the emulsified asphalt concrete will decrease when the quantity of the cement increases.
Although the additional cement can enhance a little stability and strength of the asphalt concrete, it will degrade the filling effect of the fine aggregate when the cement is hydrated. The voids of the asphalt concrete will increase, and thus degrade resistance to water immersing. Therefore, some further improvements to those traditional paving schemes become an eager desire.